Index Introduction Signs and symptoms References Introduction Parkinson's disease (PD), the second most common neurodegenerative disease after Alzheimer's disease, was originally described in 1817 by James Parkinson in the classic "Essay on shaking "Paralysis". Idiopathic Parkinson's disease (PD) still has much to discover. The rapid aging of the population, with increasing life expectancy, suggests that Parkinson's disease will become an even bigger health problem in the near future. Most cases are sporadic, although there are some clearly defined families with autosomal dominant inheritance patterns. Most of these families contain defective genes for one of several intracellular proteins. The definitive pathology in Parkinson's disease is the presence of Lewy bodies (ubiquitin-containing granules) in the cytoplasm of neurons in the degenerated substantia nigra, pars compacta (the region of dopaminergic neurons that project to the substantia nigra). It is characterized by cellular degeneration of the substantia nigra. This causes a disturbance between the neurotransmitters dopamine and acetylcholine, the balance of which allows normal movement. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essaySigns and SymptomsSymptoms do not develop until approximately 50-60% of the nigral neurons are lost and approximately 80-85% of the dopamine content of the striatum is depleted. Symptoms may include tremors, stiffness and postural problems, excessive sweating, gastrointestinal difficulties, weight loss, fatigue, pain, problems with sexual function and incontinence. Decline in cognitive function, dementia, and depression have also been reported. Symptoms can affect functional performance. Drugs can lead to the on/off phenomenon, with worsening of symptoms as the drug fails to have the desired effect. The presence of additional health problems further diversifies the Parkinson's disease experience. Four separate main groups of symptoms are usually described as part of the parkinsonism symptom complex. These groups include tremor, muscle rigidity, akinesia, and loss of normal postural fixation reflexes.4 The degree to which each of these four signs occurs in parkinsonism varies considerably from patient to patient. Tremor consists of the rhythmically alternating contraction of a given muscle group and its antagonists.4 The frequency of the tremor averages approximately 2-6 oscillations per second and is usually more evident in the distal parts of the limbs than in the proximal ones. The tremor, however, does not only affect the limbs but in some cases also the jaw, tongue, face and pectoral structures. Muscle stiffness is another important component of Parkinson's disease. The associated rigidity in Parkinson's cases is generally an impedance to passive movement present throughout the integral motor range, thus serving to differentiate rigidity from spasticity. When the intensity of the stiffness is completely similar to the range of motion, the stiffness is called "lead pipe" stiffness. In some cases of Parkinson's, however, hypertonic muscles when passively stretched show an erratic jerk in resisting movement as if being pulled through a ratchet, a condition called "cogwheel" stiffness. Stiffness may be the initial symptom of Parkinson's disease in some patients. Although resting tremor is the most dramatic symptom of Parkinson's disease, the most disabling symptom of the condition is akinesia. The term "akinesia", if taken in. 3998–4022.